quicktime quality upon repeated export from FCP ProRes HQ 50i

Is there any "LOSS of Quality on Quicktime Movies" upon reuse and repeated export out of FCP Pro Res HQ 1920x1080-50i sequence?

step 1- I have had to import batch of previously exported QT movies "A" into original edit timeline for editing and filter corrections.

step 2- which then was exported as QT movie "B"

step3- imported QT movie "B" into original edit timeline for audio sync tweaking and exported full program as QT movie "C".

step 4- imported QT movie "C" into same timeline for credits and subtitle changes. and exported program master as QTmovie"D"


I wonder what affect it has on the QUALITY of these quicktime movies?

( The source footage originally was HDV, whch was edited and renderd in ProResHQ1920x1440-50i. this includes 40% of footage converted from 60i as well as movies ripped from VCDs )

Final objective is to Lay it on HDCAM tape for TV broadcast and SD PAL DVD for retail stores.
Should I be concerned?


Program duration is 75minutes. And under duress I had to re-edit after program was mastered to tape. Initial stream of corrections took place due to artifacts caused by standards conversion.

Regards

Hoi

Quote

Is there any "LOSS of Quality on Quicktime Movies" upon reuse and repeated export out of FCP Pro Res HQ 1920x1080-50i sequence?

Yes. But it takes several passes through the encoder for the difference to be visible to the naked eye. How many is a subjective question, but the consensus seems to be an absolute minimum of ten passes, maybe more for the HQ variety of ProRes.

That said, unless you're explicitly telling Final Cut to recompress on export, you haven't actually recompressed much past step 1. If you edit some ProRes material into your timeline and don't do anything to it that requires rendering, when you export all Final Cut does is copy those frames from the source media files to your output file. Your color corrections are recompressed, obviously, as are any frames that had supers on them, but everything else is just copied, bit-for-bit, from input to output.

Thanks Jeff for your kind reply.

1- Does it matter at this stage that source footage was HDV 50i and 60i combined with DV PAL and NTSC?
OR is it that once exported as ProRes it is all upgraded to a comfort zone and well out of HDV nightmare.

2- So how about TEXT subtitles on the first batch eg QTmovie"A" ?
which has undergone import-export process about 6 times by now ( and I have been holding my breadth ).
Up till now to naked eye it looks okay but I fear it will soon start breaking up.

-Sequence Settings on export remain untouched.

- render settings remain untouched ( at ProRes HQ 50i )

1. It doesn't matter if your footage started out as a series of grainy camera-phone pictures taken of drawings done in eyeliner pencil on the back of a soggy cocktail napkin. Converting it to ProRes is not an "upgrade," in the sense that it doesn't make anything better, but from a workflow perspective it's more-or-less equivalent to converting everything to uncompressed. As I said before, after ten or twelve passes through the ProRes encoder, your footage will degrade ? eventually ? but until you hit that point, you can just close your eyes, stick your fingers in your ears and repeat, "I'm working in uncompressed, I'm working in uncompressed." It's close enough to the truth not to matter.

2. The correct way to handle burned-in titles is to keep them on a V2 layer above your footage on V1. That way you can change them to your heart's content and never stray more than one generation from the original footage.

Jeff

Indeed your stack of "grainy photos
of eyeliner pencil drawings
on the back of a soggy cocktail napkin"
provided much needed 'mortal' relief...and
yes fingers are well plugged in my ears

cheers

Jeff can we get some nice T-Shirts made up with that on?!

Jeff, quoting you from this thread:
" when you export all Final Cut does is copy those frames from the source media files to your output file.
- Your color corrections are recompressed, obviously,
- as are any frames that had supers on them,
but everything else is just copied, bit-for-bit, from input to output."


Forgive me for harping on the same but, under duress ( of third party instruction to reconfirm your technical advice) I need a clarification, ie

- "Crop", "scale" and "reposition of video " would require recompression therefore loss of quality will occur on re-exportation of quicktime.'
- re-using quicktime with previous 'Text super' WILL degrade ( Text super )after putting effects like 'crop' and 'change position' and scale on 7th generation of re-export ?

With Regards